Various automatic door locks are known for locking doors of safes and incorporate therein timing mechanisms. The majority of these locks are combination locks wherein it is necessary to punch in a code via a keypad or use special keys or tumbwheels in order to actuate a timer and/or to disengage the internal locking mechanism whereby to permit a user to retract the lockbolt by means of a lever or otherwise in order to have access to the safe. Some of these locks, however, have disadvantages in that they are bulky, are unreliable and require frequent maintenance, are not suitable for slam bolt or deadbolt use and their locking mechanism can be easily disabled by burglars.